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appearance as the alba leaf, that of a thickened evergreen leaf 
deeply grooved on the lower surface. A cross-section, however 
(Fig. IV.), shows its morphology to be very different from that of | 
alba. The leaf of alba is flat, with its blades rolled in such a way 
as to simulate a thickened leaf; that of Conradii is really thick- 
ened. That is, the central portion of the leaf is thickened and 
the edges of the blade are abruptly turned under, their margins 
nearly meeting below the lower surface, forming a furrow and 
leaving a small triangular cavity along the lower surface. As in 
alba, only the upper surface of the leaf is visible from without, 
the lower surface lining the cavity. 
Comparing now the anatomy (Fig. VI.) with that of C. alba, 
We find the cells of the upper epidermis unusually large and with 
the outer wall thickened, though usually not so much as in 
alba, These cells agree with the epidermal cells of a/éa in hav- 
ing the cellulose thickenings in the lumen. These growths occur 
in the remarkably large lumen of cells which have to sustain the 
weight of a heavily thickened cuticle. For this reason it would 
seem that their function is that of mechanical support, performing 
the same office that similar growths do in the lumen of some large 
tracheze and other thin-walled cells which have to sustain the 
Pressure of heavier tissues. In certain families, notably the 
Urticacez, there is often a deposit on the inner surface of the wall 
Of the epidermal cells in the form of cystoliths. The growths 
found in the cells under discussion, however, show none of the 
chemical reactions of cystolith formations, but in both species 
seem to be pure cellulose. The mesophyll tissue is like that 
found in alba, its development corresponding to the morphology 
of the thickened Conradii leaf. The same simple vascular system 
ceurs; the bundles have no bast element, and the whole is en- 
Closed by the endodermis sheath. 
Coming to the lower epidermis, with its accompanying stomata — 
and hairs, some differences are seen, although there are the same 
¢pidermal cells of ordinary size, the distinctly raised stomata, and 
the two forms of hairs—the long, one-celled hairs and the three- 
five-celleq capitate glands that are found in the a/éa leaf. 
The first difference noticed is the position of the simple hairs. 
Instead of being mingled with the glands over the whole lower : o : 
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